Abstract
We investigate the constraint on the split fermions in extra dimensions by considering the universality of W leptonic decays W → l i v i the charged lepton decays l i → l j v i v̄ j and the lepton flavor violating process l i → l̄ j l k l h , where l i = e, μ or τ. For the standard model (SM) background of W → l i v i , we extended the one loop quantum correction to include effects of order m l 2 /M W 2 and the Higgs boson mass dependence. We find that in general the split fermion scenarios giving rise to 4D effective Yukawa matrices of the Kaluza-Klein Higgs bosons which are misaligned with respect to the fermion mass matrix. This holds true also for gauge bosons as well. This leads to decays of l i → l̄ j l k l h at the tree level and muonium antimuonium conversion. Interestingly the leptonic universality of W boson decays are not affected at this level. © 2002 The American Physical Society.